2002 JEEP LIBERTY eco

STANDARD DIFFERENTIAL
During straight-ahead driving, the differential pin-
ion gears do not rotate on the pinion mate shaft. This
occurs because input torque applied to the gears is
divided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the
pinion mate shaft but do not rotate around it (Fig. 1).
When turning corners, the outside wheel must
travel a greater distance than the inside wheel to
complete a turn. The difference must be compensated
for to prevent the tires from scuffing and skidding
through turns. To accomplish this, the differential
allows the axle shafts to turn at unequal speeds (Fig.
2). In this instance, the input torque applied to the
pinion gears is not divided equally. The pinion gears
now rotate around the pinion mate shaft in opposite
directions. This allows the side gear and axle shaft
attached to the outside wheel to rotate at a faster
speed.
TRAC-LOKTDIFFERENTIAL
This differentials clutches are engaged by two con-
current forces. The first being the preload force
exerted through Belleville spring washers within the
clutch packs. The second is the separating forces gen-
erated by the side gears as torque is applied through
the ring gear (Fig. 3).
This design provides the differential action needed
for turning corners and for driving straight ahead
during periods of unequal traction. When one wheel
looses traction, the clutch packs transfer additional
torque to the wheel having the most traction. This
differential resist wheel spin on bumpy roads and
provide more pulling power when one wheel looses
Fig. 1 Differential Operation - Straight Ahead Driving
1 - IN STRAIGHT AHEAD DRIVING EACH WHEEL ROTATES AT
100% OF CASE SPEED
2 - PINION GEAR
3 - SIDE GEAR
4 - PINION GEARS ROTATE WITH CASE
Fig. 2 Differential Operation - On Turns
1 - PINION GEARS ROTATE ON PINION SHAFT
Fig. 3 Trac-lokTLimited Slip Differential
1 - CASE
2 - RING GEAR
3 - DRIVE PINION
4 - PINION GEAR
5 - MATE SHAFT
6 - CLUTCH PACK
7 - SIDE GEAR
8 - CLUTCH PACK
KJREAR AXLE - 8 1/4 3 - 87
REAR AXLE - 8 1/4 (Continued)

(6) Position Scooter Block/Dial Indicator flush on
the pinion height block. Hold scooter block and zero
the dial indicator.
(7) Slowly slide the scooter block across the pinion
height block over to the arbor (Fig. 13). Move the
scooter block till the dial indicator probe crests the
arbor, then record the highest reading.
(8) Select a shim equal to the dial indicator read-
ing plus the drive pinion gear depth variance number
etched/marked on the pinion (Fig. 8). For example, if
the depth variance is ±2, add +0.002 in. to the dial
indicator reading.
BEARING PRELOAD AND GEAR BACKLASH
The following must be considered when adjusting
bearing preload and gear backlash:
²The maximum ring gear backlash variation is
0.076 mm (0.003 inch).
²Mark the gears so the same teeth are meshed
during all backlash measurements.
²Maintain the torque while adjusting the bearing
preload and ring gear backlash.
²Excessive adjuster torque will introduce a high
bearing load and cause premature bearing failure.
Insufficient adjuster torque can result in excessive
differential case free-play and ring gear noise.
²Insufficient adjuster torque will not support the
ring gear correctly and can cause excessive differen-
tial case free-play and ring gear noise.
NOTE: The differential bearing cups will not always
immediately follow the threaded adjusters as they
are moved during adjustment. To ensure accurate
bearing cup responses to the adjustments:
²Maintain the gear teeth engaged (meshed) as
marked.
²The bearings must be seated by rapidly rotat-
ing the pinion gear a half turn back and forth.
²Do this five to ten times each time the threaded
adjusters are adjusted.
(1) Adjust each threaded adjuster inward with
Wrench C-4164 until the differential bearing free-
play is eliminated (Fig. 14). Allow some ring gear
backlash, approximately 0.25 mm (0.01 in.) between
the ring and pinion gear. Seat the bearing cups with
the procedure described above.
Fig. 12 Gauge Tools In Housing
1 - ARBOR DISC
2 - PINION BLOCK
3 - ARBOR
4 - PINION HEIGHT BLOCK
Fig. 13 Pinion Gear Depth Measurement
1 - ARBOR
2 - SCOOTER BLOCK
3 - DIAL INDICATOR
Fig. 14 Threaded Adjuster
1 - AXLE TUBE
2 - BACKING PLATE
3 - ADJUSTER WRENCH
3 - 94 REAR AXLE-81/4KJ
REAR AXLE - 8 1/4 (Continued)

SIDE GEAR CLEARANCE
NOTE: When measuring side gear clearance, check
each gear independently. If it necessary to replace a
side gear, replace both gears as a matched set.
(1) Install the axle shafts, C-locks and pinion mate
shaft.
(2) Measure each side gear clearance. Insert a
matched pair of feeler gauge blades between the gear
and differential housing on opposite sides of the hub
(Fig. 17).
(3) If side gear clearances is no more than 0.005
inch. Determine if the axle shaft is contacting the
pinion mate shaft.Do not remove the feeler
gauges, inspect the axle shaft with the feeler
gauge inserted behind the side gear.If the end ofthe axle shaft is not contacting the pinion mate
shaft, the side gear clearance is acceptable.
(4) If clearance is more than 0.005 inch (axle shaft
not contacting mate shaft), record the side gear clear-
ance. Remove the thrust washer and measure its
thickness with a micrometer. Add the washer thick-
ness to the recorded side gear clearance. The sum of
gear clearance and washer thickness will determine
required thickness of replacement thrust washer
(Fig. 18).
In some cases, the end of the axle shaft will move
and contact the mate shaft when the feeler gauge is
inserted. The C-lock is preventing the side gear from
sliding on the axle shaft.
(5) If there is no side gear clearance, remove the
C-lock from the axle shaft. Use a micrometer to mea-
sure the thrust washer thickness. Record the thick-
ness and re-install the thrust washer. Assemble the
differential case without the C-lock installed and re-
measure the side gear clearance.
(6) Compare both clearance measurements. If the
difference is less than 0.012 inch (0.305 mm), add
clearance recorded when the C-lock was installed to
thrust washer thickness measured. The sum will
determine the required thickness of the replacement
thrust washer.
(7) If clearance is 0.012 inch (0.305 mm) or
greater, both side gears must be replaced (matched
set) and the clearance measurements repeated.
(8) If clearance (above) continues to be 0.012 inch
(0.305 mm) or greater, the case must be replaced.
Fig. 17 Side Gear Clearance
1 - FEELER GAUGE BLADES
2 - SIDE GEAR
Fig. 18 Side Gear Calculations
KJREAR AXLE - 8 1/4 3 - 97
REAR AXLE - 8 1/4 (Continued)

(7) Measure rotating torque of the pinion gear
with an inch pound torque wrench and record the
reading for installation reference.
(8) Hold the pinion yoke with Holder 6719 and
remove the pinion nut and washer.
(9) Remove yoke with Remover C-452 (Fig. 24).
(10) Remove pinion seal with a pry tool or screw
mounted to a slide-hammer mounted.
INSTALLATION
(1) Apply a light coating of gear lubricant on the
lip of pinion seal.
NOTE: The outer perimeter of the seal is pre-coated
with a special sealant. An additional application of
sealant is not required.
(2) Install thenewpinion seal (Fig. 25) with
Installer C-4076-A and Handle C-4735.
(3) Install pinion yoke on the shaft with the refer-
ence marks aligned.
(4) Seat yoke on pinion shaft with Installer C-3718
and Holder 6719A.
(5) Remove the tools and install the pinion yoke
washer. The convex side of the washer must face out-
ward.
(6) Using yoke Holder 6719A tighten shaft nut to
285 N´m (210 ft. lbs.) (Fig. 26). Rotate the pinion sev-
eral revolutions to ensure the bearing rollers are
seated.
(7) Rotate the pinion using an inch pound torque
wrench. Rotating torque should be equal to the read-
ing recorded during removal, plus an additional 0.56
N´m (5 in. lbs.) (Fig. 27).CAUTION: Never loosen pinion nut to decrease pin-
ion rotating torque and never exceed specified pre-
load torque. If preload torque is exceeded a new
collapsible spacer must be installed.
(8) If the rotating torque is low, use Holder 6719A
(Fig. 26) and tighten the pinion nut in 6.8 N´m (5 ft.
Fig. 24 Pinion Yoke
1 - PINION YOKE
2 - REMOVER
Fig. 25 Pinion Seal Installer
1 - HANDLE
2 - DIFFERENTIAL HOUSING
3 - INSTALLER
Fig. 26 Tightening Pinion Nut
1 - DIFFERENTIAL HOUSING
2 - YOKE HOLDER
3 - TORQUE WRENCH
KJREAR AXLE - 8 1/4 3 - 103
PINION SEAL (Continued)

DISASSEMBLY
(1) Clamp side gear Fixture 8138 in a vise and set
differential case on the fixture (Fig. 35).
(2) Remove ring gear if the ring gear is to be
replaced. The Trac-loktdifferential can be serviced
with the ring gear installed.
(3) Remove pinion gear mate shaft lock screw.
(4) Remove pinion gear mate shaft with a drift and
hammer.
(5) Install Discs 8140 without threaded hole in the
lower side gear (Fig. 36).
(6) Install Disc 8140 with threaded hole in the
upper side gear. Thread Forcing Screw 6960-4
through the upper disc until it becomes centered in
lower disc.
(7) Insert a screw driver in slot of upper disc (Fig.
37) to prevent disc from turning.
Fig. 36 LOWER DISC
1 - LOWER SIDE GEAR
2 - DIFFERENTIAL CASE
3 - DISC
Fig. 37 TRAK-LOCTTOOLS
1 - SOCKET
2 - SLOT IN DISC
3 - SCREWDRIVER
4 - LOWER DISC
5 - THREADED ROD
6 - UPPER DISC
Fig. 35 DIFFERENTIAL CASE FIXTURE
1 - FIXTURE
2 - VISE
3 - DIFFERENTIAL
KJREAR AXLE - 8 1/4 3 - 107
DIFFERENTIAL - TRAC-LOK (Continued)

(10) Remove pinion shaft seal with a pry tool or
slide-hammer mounted screw.
(11) Remove oil slinger, if equipped, and front pin-
ion bearing.
(12) Remove front pinion bearing cup with
Remover C-4345 and Handle C-4171 (Fig. 50).
(13) Remove rear bearing cup from housing (Fig.
51) with Remover C-4307 and Handle C-4171.
(14) Remove collapsible preload spacer (Fig. 52).
(15) Remove rear bearing from the pinion (Fig. 53)
with Puller/Press C-293-PA and Adapters C-293-47.
(16) Remove depth shims from the pinion shaft
and record the shims thickness.
INSTALLATION
NOTE: A pinion depth shim/oil baffle is placed
between the rear pinion bearing cone and pinion
gear. If the ring and pinion gears are reused, the
original pinion depth shim/oil baffle can be used.
Refer to Adjustments (Pinion Gear Depth) to select
the proper shim thickness if ring and pinion gear
are replaced.
(1) Apply Mopar Door Ease or equivalent lubricant
to outside surface of pinion bearing cups.
(2) Install rear pinion bearing cup (Fig. 54) with
Installer C-4308 and Handle C-4171 and verify cup is
seated.(3) Install front pinion bearing cup (Fig. 55) with
Installer D-130 and Handle C-4171 and verify cup is
seated.
Fig. 50 Front Pinion Bearing Cup
1 - REMOVER
2 - HANDLE
Fig. 51 Rear Pinion Bearing Cup
1 - DRIVER
2 - HANDLE
Fig. 52 Collapsible Spacer
1 - COLLAPSIBLE SPACER
2 - SHOULDER
3 - PINION
4 - PINION DEPTH SHIM
5 - REAR BEARING
3 - 112 REAR AXLE-81/4KJ
PINION GEAR/RING GEAR/TONE RING (Continued)

DIAGNOSIS AND TESTING - MASTER
CYLINDER/POWER BOOSTER...........21
REMOVAL.............................22
INSTALLATION.........................23
MASTER CYLINDER
DESCRIPTION.........................24
OPERATION...........................24
DIAGNOSIS AND TESTING - MASTER
CYLINDER/POWER BOOSTER...........24
STANDARD PROCEDURE - MASTER
CYLINDER BLEEDING..................24
REMOVAL.............................25
INSTALLATION.........................25
FLUID RESERVOIR
REMOVAL.............................26
INSTALLATION.........................26
FLUID
DIAGNOSIS AND TESTING - BRAKE FLUID
CONTAMINATION.....................26
STANDARD PROCEDURES - MASTER
CYLINDER FLUID LEVEL................26
SPECIFICATIONS
BRAKE FLUID........................27
DRUM
DIAGNOSIS AND TESTING - BRAKE DRUM . . . 27
STANDARD PROCEDURES - BRAKE DRUM
MACHINING..........................27SUPPORT PLATE
REMOVAL
REMOVAL - 198 RBI AXLE..............27
REMOVAL - 8 1/4 AXLE.................27
INSTALLATION
INSTALLATION - 198 RBI AXLE...........28
INSTALLATION - 8 1/4 AXLE.............28
WHEEL CYLINDERS
REMOVAL.............................28
DISASSEMBLY.........................28
CLEANING............................28
INSPECTION..........................29
ASSEMBLY............................29
INSTALLATION.........................29
PARKING BRAKE
DESCRIPTION.........................29
OPERATION...........................29
ADJUSTMENTS
ADJUSTMENT - LOCK OUT.............30
CABLES
REMOVAL.............................30
INSTALLATION.........................30
LEVER
REMOVAL.............................31
INSTALLATION.........................31
BRAKES - BASE
DESCRIPTION
Power assist front disc and rear drum brakes are
standard equipment. Disc brake components consist
of single piston calipers and ventilated rotors. Rear
drum brakes are dual shoe units with cast brake
drums.
The parking brake mechanism is lever and cable
operated. The cables are attached to levers on the
rear drum brake secondary shoes. The parking
brakes are operated by a hand lever.
A dual diaphragm vacuum power brake booster is
used for all applications. All models have an alumi-
num master cylinder with plastic reservoir.
All models are equipped with a combination valve.
The valve contains a pressure differential valve and
switch and a fixed rate rear proportioning valve.
Factory brake lining on all models consists of an
organic base material combined with metallic parti-
cles. The original equipment linings do not contain
asbestos.
WARNING
WARNING: DUST AND DIRT ACCUMULATING ON
BRAKE PARTS DURING NORMAL USE MAY CON-
TAIN ASBESTOS FIBERS FROM AFTERMARKET
LININGS. BREATHING EXCESSIVE CONCENTRA-
TIONS OF ASBESTOS FIBERS CAN CAUSE SERI-
OUS BODILY HARM. EXERCISE CARE WHEN
SERVICING BRAKE PARTS. DO NOT CLEAN
BRAKE PARTS WITH COMPRESSED AIR OR BY
DRY BRUSHING. USE A VACUUM CLEANER SPE-
CIFICALLY DESIGNED FOR THE REMOVAL OF
ASBESTOS FIBERS FROM BRAKE COMPONENTS.
IF A SUITABLE VACUUM CLEANER IS NOT AVAIL-
ABLE, CLEANING SHOULD BE DONE WITH A
WATER DAMPENED CLOTH. DO NOT SAND, OR
GRIND BRAKE LINING UNLESS EQUIPMENT USED
IS DESIGNED TO CONTAIN THE DUST RESIDUE.
DISPOSE OF ALL RESIDUE CONTAINING ASBES-
TOS FIBERS IN SEALED BAGS OR CONTAINERS
TO MINIMIZE EXPOSURE TO YOURSELF AND OTH-
ERS. FOLLOW PRACTICES PRESCRIBED BY THE
OCCUPATIONAL SAFETY AND HEALTH ADMINIS-
TRATION AND THE ENVIRONMENTAL PROTECTION
AGENCY FOR THE HANDLING, PROCESSING, AND
DISPOSITION OF DUST OR DEBRIS THAT MAY
CONTAIN ASBESTOS FIBERS.
5 - 2 BRAKES - BASEKJ

CAUTION: Never use gasoline, kerosene, alcohol,
motor oil, transmission fluid, or any fluid containing
mineral oil to clean the system components. These
fluids damage rubber cups and seals. Use only
fresh brake fluid or Mopar brake cleaner to clean or
flush brake system components. These are the only
cleaning materials recommended. If system contam-
ination is suspected, check the fluid for dirt, discol-
oration, or separation into distinct layers. Also
check the reservoir cap seal for distortion. Drain
and flush the system with new brake fluid if con-
tamination is suspected.
CAUTION: Use Mopar brake fluid, or an equivalent
quality fluid meeting SAE/DOT standards J1703 and
DOT 3. Brake fluid must be clean and free of con-
taminants. Use fresh fluid from sealed containers
only to ensure proper antilock component opera-
tion.
CAUTION: Use Mopar multi-mileage or high temper-
ature grease to lubricate caliper slide surfaces,
drum brake pivot pins, and shoe contact points on
the backing plates. Use multi-mileage grease or GE
661 or Dow 111 silicone grease on caliper slide pins
to ensure proper operation.
DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM
Base brake components consist of the brake shoes,
calipers, wheel cylinders, brake drums, rotors, brake
lines, master cylinder, booster, and parking brake
components.
Brake diagnosis involves determining if the prob-
lem is related to a mechanical, hydraulic, or vacuum
operated component.
The first diagnosis step is the preliminary check.
PRELIMINARY BRAKE CHECK
(1) Check condition of tires and wheels. Damaged
wheels and worn, damaged, or underinflated tires
can cause pull, shudder, vibration, and a condition
similar to grab.
(2) If complaint was based on noise when braking,
check suspension components. Jounce front and rear
of vehicle and listen for noise that might be caused
by loose, worn or damaged suspension or steering
components.
(3) Inspect brake fluid level and condition. Note
that the brake reservoir fluid level will decrease in
proportion to normal lining wear.Also note that
brake fluid tends to darken over time. This is
normal and should not be mistaken for contam-
ination.(a) If fluid level is abnormally low, look for evi-
dence of leaks at calipers, wheel cylinders, brake
lines, and master cylinder.
(b) If fluid appears contaminated, drain out a
sample to examine. System will have to be flushed
if fluid is separated into layers, or contains a sub-
stance other than brake fluid. The system seals
and cups will also have to be replaced after flush-
ing. Use clean brake fluid to flush the system.
(4) Check parking brake operation. Verify free
movement and full release of cables and pedal. Also
note if vehicle was being operated with parking
brake partially applied.
(5) Check brake pedal operation. Verify that pedal
does not bind and has adequate free play. If pedal
lacks free play, check pedal and power booster for
being loose or for bind condition. Do not road test
until condition is corrected.
(6) Check booster vacuum check valve and hose.
(7) If components checked appear OK, road test
the vehicle.
ROAD TESTING
(1) If complaint involved low brake pedal, pump
pedal and note if it comes back up to normal height.
(2) Check brake pedal response with transmission
in Neutral and engine running. Pedal should remain
firm under constant foot pressure.
(3) During road test, make normal and firm brake
stops in 25-40 mph range. Note faulty brake opera-
tion such as low pedal, hard pedal, fade, pedal pulsa-
tion, pull, grab, drag, noise, etc.
(4) Attempt to stop the vehicle with the parking
brake only and note grab, drag, noise, etc.
PEDAL FALLS AWAY
A brake pedal that falls away under steady foot
pressure is generally the result of a system leak. The
leak point could be at a brake line, fitting, hose, or
caliper/wheel cylinder. If leakage is severe, fluid will
be evident at or around the leaking component.
Internal leakage (seal by-pass) in the master cylin-
der caused by worn or damaged piston cups, may
also be the problem cause.
An internal leak in the ABS or RWAL system may
also be the problem with no physical evidence.
LOW PEDAL
If a low pedal is experienced, pump the pedal sev-
eral times. If the pedal comes back up worn linings,
rotors, drums, or rear brakes out of adjustment are
the most likely causes. The proper course of action is
to inspect and replace all worn component and make
the proper adjustments.
KJBRAKES - BASE 5 - 3
BRAKES - BASE (Continued)